SQLite 3.27

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CREATE TABLE tablename (`col1` INTEGER, `col2` TEXT);
✓
INSERT INTO tablename (`col1`, `col2`) VALUES
  ('1', '{"id":"id1", "value":"value1"}'),
  ('2', '{"id":"id2", "value":"value2, value3"}'),
  ('3', '{"id":"id3", "value":"value4, value5"}');
✓
select group_concat(json_extract(col2, '$.value'), ', ') result
from tablename

{
  "code": "SQLITE_ERROR"
}


select replace(json_group_array(json_extract(col2, '$.value')), ', ', '","') result
from tablename

{
  "code": "SQLITE_ERROR"
}


select group_concat(substr(
         col2, 
         instr(col2, '"value":"') + length('"value":"'), 
         length(col2) - (instr(col2, '"value":"') + length('"value":"') + 1)
       ), ', ') result
from tablename


result


value1, value2, value3, value4, value5